Trees to 18 m tall; bark grayish black, irregularly furrowed, Branchlets pendulous, brownish yellow, brownish, or slightly purple, slender, glabrous. Buds linear, apex acute. Stipules lanceolate or ovate-orbicular, those of shoots obliquely lanceolate; petiole (3-)5-10 mm; leaf blade narrowly lanceolate or linear-lanceolate, 9-16 × 0.5-1.5 cm, abaxially light green, adaxially green, both surfaces glabrous or slightly pilose, base cuneate, margin serrate, apex long acuminate. Male catkin 1.5-2(-3) cm; peduncle short; bracts lanceolate, abaxially pilose. Male flower: glands 2; stamens 2, ca. as long as to longer than bracts, ± long pubescent at base; anthers reddish yellow. Female catkin 2-3(-6) cm, with 3 or 4 leaves on peduncle; bracts lanceolate, 1.8-2(-2.5) mm, abaxially pilose. Female flower: gland adaxial; ovary ellipsoid, glabrous or minutely pubescent proximally, sessile or subsessile; style short; stigma 2-4-parted. Capsule slightly greenish brown, 3-4 mm. Fl. Mar-Apr, fr. Apr-May. 2n = 63, 72, 76.
Stems: branches yellow-brown to red-brown; branchlets sparsely to moderately densely tomentose, especially at nodes. Leaves: stipules absent or rudimentary on early ones; petiole convex to flat or shallowly to deeply grooved adaxially, 7-9 mm, tomentose abaxially; largest medial blade lanceolate, narrowly oblong, or narrowly elliptic, 90-160 × 5-20 mm, 5.5-10.5 times as long as wide, base cuneate, margins flat, spinulose-serrulate or serrulate, apex acuminate, caudate, or acute, surfaces glabrous or sparsely short-silky, hairs straight, dull adaxially; proximal blade margins entire; juvenile blade reddish or yellowish green. Catkins (flowering just before leaves emerge); staminate 13-35 mm, flowering branchlet 1-6 mm; pistillate densely flowered, stout or subglobose, 9-27 × 2.5-7 mm, flowering branchlet (0-)2-4 mm; floral bract 1.1-1.8 mm, apex acute, rounded, or truncate, entire, abaxially sparsely hairy throughout or proximally, hairs wavy. Staminate flowers: abaxial nectary 0.2-0.6 mm, adaxial nectary oblong or ovate, 0.4-0.7 mm, nectaries distinct or connate and cup-shaped; filaments distinct, hairy on proximal 1/2 or basally; anthers (sometimes reddish turning yellow), ellipsoid or globose. Pistillate flowers: adaxial nectary oblong, square, ovate, or obovate, 0.4-0.8 mm; ovary ovoid or obturbinate, beak (sometimes pilose proximally), slightly bulged below or abruptly tapering to styles; ovules 2-4 per ovary; styles distinct or connate 1/2 their lengths, 0.2-0.3 mm; stigmas flat, abaxially non-papillate with rounded tip, or 2 plump lobes (almost capitate), 0.2-0.3 mm. Capsules 2-2.7 mm. 2n = 76.
"Tree to 12 m, the cult. and escaped forms with long, slender, pendulous, olivaceous or yellow-brown, glabrous or subglabrous, basally brittle twigs; stipules lanceolate, 2–7 mm, or none; lvs lance-linear, 8–12 × 0.5–1.5 cm, mostly falcate, long-acuminate, finely but unevenly spinulose- serrulate, glabrous, yellowish-green above, ± glaucous beneath; petioles 7–12 mm, tomentose, often glandular above at the tip; catkins with the lvs, 1–2.5 (staminate to 4) cm, on peduncles 0.5–1.5 cm with 2–4 tiny lvs; scales pale yellow, crinkly-hairy, ± persistent; stamens 2; frs narrowly ovoid, 1.5-2.5 mm, sessile; style almost obsolete; stigmas brush-like (unique among our spp.); 2n=76. Native of China, sparingly escaped from cult. in our range."